Wavelength-of-he-ne-laser-by-diffraction-grating-experiment, with the new laser he-ne (described in the laser he-ne post), you can easily test the physical properties of the diffraction grating.we propose, in particular, to measure the pitch of the grating through the measurement of the diffraction produced on the he-ne laser beam.. By shining a light beam into a grating whose spacing d is known, and measuring the angle θ where the light is imaged, one can measure the wavelength λ. this is the manner in which the atomic spectra of various elements were first measured., when light of a single wavelength , like the 632.8nm red light from a helium-neon laser at left, strikes a diffraction grating it is diffracted to each side in multiple orders. orders 1 and 2 are shown to each side of the direct beam. different wavelengths are diffracted at different angles, according to the grating relationship..

6 the scheme for term work assessment 1. the term work for engineering physics is for 25 marks 2. there is no exam for experiments 3. while assessing the term work, 60% weightage is for performing the experiments and, the purpose of this lab is to experimentally determine the wavelength of a helium-neon laser by using a reflection grating.